There have been known a antifoam agent comprising an alkaline earth metal salt of a fatty acid, a dialkyl ester of an unsaturated dicarboxylic acid, a mineral oil, a non-ionic emulsifier, an anion emulsifier, and alkylenediamide (patent document 1), and a defoaming agent composition comprising a base oil composed of a liquid hydrocarbon oil, an amide derivative of a fatty acid, and a metallic soap (patent document 2).